1. Field of the Invention
The present invention relates to a float textile having an optical function and, more specifically, to a float textile formed of multi-filament yarn having the optical function of developing color by the reflection, interference, diffraction or scattering of light.
2. Prior Art
In recent years, to meet demand for cloth having a quality feel, a bulked fiber has been developed as a new synthetic fiber by changing the cross sectional form of the fiber from a simple round form to a different form and by combining two or more different fibers. Fibers having higher feeling and more advanced functions are now in demand. One of them is a fiber having a color deepness and gloss. When a color deepness and gloss are to be attained at the same time, a color deepness effect is obtained but the color of the fiber becomes dull and not bright any more. On the other hand, when a gloss is to be attained, a facinated light is not obtained. There has been no technology for attaining the both functions. The reason for this is that the intensity of reflected light decreases as a higher color deepness effect is to be obtained with the result of the disappearance of a gloss because a color is developed by a dye or pigment, that is, a color is developed by the absorption of light in the prior art.
Meanwhile, looking at around the world of nature, for example, Chrysochroa fulgidissima and Morpho butterfly have a color deepness and gloss and show a color completely different from a color developed by a dye or pigment. This color development mechanism is due to the reflection and interference of light. Even in synthetic fibers, various measures have been taken to make use of this mechanism. For example, JP-A 7-34320, JP-A 7-34324 and JP-A 7-331532 (the term xe2x80x9cJP-Axe2x80x9d as used herein means unexamined published Japanese patent application) disclose a optically interfering flat mono-filament having a multi-layer thin film structure formed by laminating polymers having different refractive indices (optical refractive indices) alternately and a flattening ratio of 3.5 or less.
Natural light incident upon this optically interfering mono-filament ideally develops a reflection spectrum based on multi-layer thin film interference, that is, an interference color. In fact, part of natural light transmits, refracts or scatters due to the imperfection of the structure of the mono-filament (such as a difference in thickness between polymer layers and a difference in crystallinity between used polymers), dependence upon wavelength of refractive index (polymer dispersibility) and dependence upon wavelength of absorption coefficient and functions as so-called xe2x80x9cstray lightxe2x80x9d. This means that a reflection component based on the above stray light is superimposed upon the reflection spectrum based on the multi-layer thin film interference, thereby impairing the original bright color. Therefore, the above JP-A 7-331532 proposes a technology for interweaving an optically interferring mono-filament with a black-colored spun-dyed fiber to plain weave, twill weave or satin weave to prevent the above stray light.
Further, although a multi-filament yarn is generally used in the filament textile, when the multi-filament yarn prepared by bundling the above mono-filaments is simply used in combination with a densely color fiber, the effect of removing stray light is obtained but a color based on optical interference which is originally intended is not always expressed. Therefore, JP-A 11-107109 proposes a float textile woven of multi-filaments as a float component formed of optically interfering mono-filaments having a flattening ratio of 4 to 15 as a constituent unit.
However, it has been found that, according to application purpose, particularly room interior and car interior fields, a large number of optically interfering flat mono-filaments to be bundled is necessary in a floating portion of the texture and that the textile of JP-A 11-107109 does not always exhibit a color development effect to the full.
That is, when the above-explained optically interfering mono-filament is supplied for weaving, there are proposed (1) a method in which a sizing agent is applied to yarn in a zero-twisted state and (2) a method in which yarn is twisted. However, in the method (1), the sizing agent adhered to the surface of yarn reduces the color development and a desired color cannot be always obtained. Further, the sizing agent may fall off at the time of weaving, thereby impairing productivity. In the method (2), since the filament is axially twisted, reflected light which is color developing light is scattered and weakened with the result that the color development effect of the filament cannot be exhibited to the full.
It is an object of the present invention to provide a textile which can exhibit the bright color development effect of an optically interfering flat mono-filament even when a large number of multi-filaments each formed of the above mono-filaments as a constituent unit are bundled.
The inventors of the present invention have found that the reason why the color development effect of yarn as a whole cannot be exhibited to the full when a large number of the above optically interfering flat multi-filaments are bundled is the axial twisting of the flat filament. The present invention has been accomplished based on this finding.
Thus, according to the present invention, there is provided a float textile having an optical interference function, containing a float texture that yarn formed by combining three or more multi-filament yarns each comprising, as a constituent unit, optically interfering mono-filaments which are formed by alternately laminating layers of at least two polymers having different refractive indices and which have a flattening ratio of 4 to 15 and by interlacing the 3 or more multi-filament yarns to form 20 or less interlaces per meter is used as a warp float and/or weft float component, and having a float number of 2 or more.